Overall there is no best; people are in it for different things. Each program has its own personality so honestly, you need to figure out what you're looking for; Hospital programs >>> University programs unless your main focus is teaching, imo.
Top 3 hospital programs in my opinion:
Children's Hospital of Pittsburgh: A bit of a sleeper but most people that extern/visit love it. Brand new facility, faculty seemed to be a different level compared to other places (good thing to be surrounded by), the day to day is very well organized. The residents were flying / working extremely hard but were done by 5 every day. This is important, imo, as many other programs you're there past 6-7 doing paperwork. Awesome sedation experience (arguably the best or one of the best out of any program in the nation). The actual flow/design of the day is practical (hygiene checks in between patients but not doing your own hygiene, schedule is relatively fluid so any time resident finishes early they take the next available patient, etc). Residents very happy but definitely a program you're going to work hard. Seemed to be very balanced in terms of seeing complex cases as well as normal bread and butter. I don't think the research component was as strong as OSU/other university programs.
Possible downside: faculty see their own patients so they are around if you need them but not sitting around waiting for you (if you need your hand held, not the program for you).
OSU/Nationwide: Slower pace than ^^ but definitely focused on patient care as the priority without making any sacrifices to learning (Ie. You dont go into OR until second year because first year you are slow and the longer the patient is under, the worse it is for their health). Brand new facility being built currently (might be done?), lots of faculty always available. A few of the well known faculty have left to run other programs or are retiring but still one of the most stacked in terms of teaching clout. You also get your masters without having to do an additional year. Faculty are always around / willing to give advice. The reputation of the program is sterling and well known, if that means anything to you. I believe they take 8 residents a year so less call compared to other programs but still see plenty of trauma/emergencies. It felt like the program was very responsive to the residents wants/wishes and also had the budget to make it happen (Ie. residents feel like they're lacking in something and bring it up, the faculty will bolster that immediately). Very well rounded and didn't seem like anything was lacking.
Cincinatti: Similar feel to OSU (I believe the chair worked at OSU/childrens for a while before running the program at cinci). Older facility and a bit more of a focus on sedation/OR experience and less on the research. Very solid program, very good reputation. Residents were extremely happy here as well.
Honorable mentions:
Boston Childrens: Incredible experience (very complex health patients referred from other programs would end up here), international name recognition and ability to see some amazing cases. Reason not top 3: Residents were definitely overworked and stressed. Most days they'd stay there until 8-9pm, by second year maybe done by 7-8pm. It didn't seem like it was because they were seeing many more patients than other programs, just seemed like a lot of paperwork/scud work that made the days long.
Wisconsin Childrens: Well run, ortho experience was probably one of the best (6 cases guaranteed as its set up for you right as you start residency). Seemed to be a bit more hand holding (I believe they did prep checks for the first few months) but residents were happy. Downsides: You're in Wisconsin.
Places that have good reputation but did not personally visit/interview:
Colorado (required ADAT, though this might be changing)
Baylor